Human Milk Oligosaccharides in the Milk of Mothers Delivering Term versus Preterm Infants

Abstract

Human milk oligosaccharides (HMOs) are a major component of human milk, and play an important role in protecting the infant from infections. Preterm infants are particularly vulnerable, but have improved outcomes if fed with human milk. This study aimed to determine if the HMO composition of preterm milk differed from that of term milk at equivalent stage of lactation and equivalent postmenstrual age. In all, 22 HMOs were analyzed in 500 samples of milk from 25 mothers breastfeeding very preterm infants (< 32 weeks of gestational age, < 1500g of birthweight) and 28 mothers breastfeeding term infants. The concentrations of most HMOs were comparable at equivalent postpartum age. However, HMOs containing α-1,2-linked fucose were reduced in concentration in preterm milk during the first month of lactation. The concentrations of a number of sialylated oligosaccharides were also different in preterm milk, in particular 3'-sialyllactose concentrations were elevated. At equivalent postmenstrual age, the concentrations of a number of HMOs were significantly different in preterm compared to term milk. The largest differences manifest around 40 weeks of postmenstrual age, when the milk of term infants contains the highest concentrations of HMOs. The observed differences warrant further investigation in view of their potential clinical impact.

Keywords: 2′-fucosyllactose (2′FL); 3′-sialyllactose (3′SL); Lewis; disialyllacto-N-tetraose (DSLNT); human milk oligosaccharides (HMO); lactation; milk group; preterm; secretor.

Figure 1

Example of milk sampling scheme from term and preterm mothers delivering at postmenstrual weeks 40 and 30 respectively. Reprinted from Garcia-Rodenas, et al. Clinical Nutrition, 2018 [44] with kind permission from Elsevier.

Figure 2

Distribution of milk groups in the different populations: All = all participants, P = participants with preterm infants, T = participants with term infants, G1 = milk group 1, G2 = milk group 2, G3 = milk group 3, G4 = milk group 4.

Figure 3

Mean concentration of each HMO at each visit for term (grey) and preterm (white) infants, letters indicate if difference between term and preterm is significant; a: p < 0.05, b: p < 0.005, c: p < 0.0005.

Figure 4

Comparison of HMO concentrations in group 1 term (grey bars) and preterm (white bars) milk. a: p < 0.05, b: p < 0.005 c: p < 0.0005.

Figure 5

Comparison of selected HMO concentrations in group 1 (G1) and group 2 (G2) term (grey bars) and preterm (white bars) milk. a: p < 0.05, b: p < 0.005 c: p < 0.0005. Significance not tested in G2 milk due to low number of subjects (5 for each arm).

Figure 6

Comparison of the HMO concentration in the milk of mothers giving birth to term (grey bars) or preterm (white bars) infants at equivalent postmenstrual age. a: p < 0.05, b: p < 0.005 c: p < 0.0005.

Figure 7

Comparison of the HMO concentration in group 1 milk of mothers giving birth to term (grey bars) or preterm (white bars) infants at equivalent gestational age. a: p < 0.05, b: p < 0.005 c: p < 0.0005.